Search in
Sort by:

Question Status:

Search help

  • Simple searches use one or more words. Separate the words with spaces (cat dog) to search cat,dog or both. Separate the words with plus signs (cat +dog) to search for items that may contain cat but must contain dog.
  • You can further refine your search on the search results page, where you can search by keywords, author, topic. These can be combined with each other. Examples
    • cat dog --matches anything with cat,dog or both
    • cat +dog --searches for cat +dog where dog is a mandatory term
    • cat -dog -- searches for cat excluding any result containing dog
    • [cats] —will restrict your search to results with topic named "cats"
    • [cats] [dogs] —will restrict your search to results with both topics, "cats", and "dogs"

GPU Emitter Not Working Properly


So I realized something wrong was going on with my GPU emitters. They are not spamming as much as they use to, and the spam is inconsistent.

Let me show with pics;

Here is a GPU Particle Emitter of 4.10 . Its nothing but the standard one. Only things I included is an "initial velocity of 150-X" and "size by life going from 1 to 0 in one second" nodes. I am spamming the particle for 5000 times aswell.

Here is 4.10, all smooth;

alt text

Here is 4.11, with hiccups;

alt text

When you do it with a circle texture, its more obvious;

Here is 4.10;

alt text

And 4.11, obvious hiccups;

alt text

I will gladly help with any questions. It's easy to produce so. Thanks!

Product Version: UE 4.11
capture2.png (31.6 kB)
capture.png (45.6 kB)
capture3.png (7.5 kB)
capture4.png (7.4 kB)
more ▼

asked Apr 01 '16 at 05:44 PM in Bug Reports

avatar image

782 38 34 70

avatar image Tim Hobson ♦♦ STAFF Apr 01 '16 at 08:35 PM

Hi Achilleon,

I've entered UE-29009 for this to be investigated.

Thank you!


avatar image Achilleon Apr 06 '16 at 11:24 PM

Mr Tim,

Thank you for your time. I just want to let you know that the same problem is happening with ribbon data emitters too, and to a worse degree if I might add.

Just wanted to point out.

avatar image Tim Hobson ♦♦ STAFF Apr 07 '16 at 02:17 PM

Got that one and reported it a few days ago with UE-29078. ;)

We're going to try and get these pushed out in a HotFix for 4.11 since they can impact more users, but unfortunately I can't guarantee that will happen just yet. If they are in the HotFix they will be listed on the Update notes from the forums.

avatar image Adder1812 Apr 04 '16 at 01:37 PM

Same thing here. I'm going nuts!

(comments are locked)
10|2000 characters needed characters left
Viewable by all users

1 answer: sort voted first

This was a deliberate change from what the ticket says.

Here are the notes from the ticket.

"If the user wants to target higher framerates while not supporting "low" framerates, he can disable the feature with: "r.GPUParticle.FixDeltaSeconds 0"

If he puts a too small value like "r.GPUParticle.FixDeltaSeconds .005", then low framerate systems will suffer extra cost because the simulation will be done several times (to the extent of "r.GPUParticle.MaxNumIterations") This is definitely a new behavior compared with the previous version, but to some extent the system must be designed to look acceptable at framerates around 30-60 fps. This special case binding the frame rate to the particle system look is what was intented to be fixed by the FixDeltaSeconds feature (it goes for high framerates as well a "slomo" replay)."

Thank you!


more ▼

answered Apr 29 '16 at 08:27 PM

avatar image

Tim Hobson ♦♦ STAFF
48.8k 888 103 878

avatar image Achilleon Apr 30 '16 at 10:42 AM

This seems to be a very hideous "fix" Mr Tim. It's not that I will judge, but is it okay if I use that exec command on level blueprint with Begin Play Event?

Will that fix it? I am asking this as I am no longer using the GPU particle. Or won't be for long. I just want to know if its possible that way or not. Thanks!

avatar image Tim Hobson ♦♦ STAFF May 02 '16 at 01:29 PM

The problem with the original repro case, and the one I submitted the bug for was a very specific way to reproduce the issue. Using the methods mentioned above are going to be best practice for particle systems in this manner.

(comments are locked)
10|2000 characters needed characters left
Viewable by all users
Your answer
toggle preview:

Up to 5 attachments (including images) can be used with a maximum of 5.2 MB each and 5.2 MB total.

Follow this question

Once you sign in you will be able to subscribe for any updates here

Answers to this question